Identifies which version of the Tag Set, named in the DOCTYPE declaration, was used to make the article under consideration, which therefore should be used to validate this article
This is a “fixed” attribute (meaning that the value is set via a parameter entity; thus, an author or editor cannot change it) that should change every time this Tag Set changes versions or revisions.
| Value | Meaning |
|---|---|
| 0.1 | Initial draft of the DTD, pre-release |
| Restriction: |
|